<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>041-盒模型内外边距.html</title>
	<style>
		.father{
			width: 400px;
			border: 1px solid #000;
			padding: 20px;
		}
		.father div{
			width: 100px;
			height: 100px;
			background: gray;
		}
		.son2{
			margin-top: 40px;
		}
	</style>
</head>
<body>
	<div class="father">
		<div class="son1"></div>
		<div class="son2"></div>
	</div>
</body>
</html>